Semi-automatic and full-automatic operation of gas-operated firearm with slidable barrel and slidable receiver



Sept. 19, 1961 o. B. VARONA 3,090,265

SEMI-AUTOMATIC AND FULL-AUTOMATIC OPERATION OF GAS-OPERATED FIREARM WITH SLIDABLE BARREL AND SLIDABLE RECEIVER 5 Sheets-Sheet 1 Filed July 29, 1959 5 Wm N INVENTOR. 0564/ bz/fiw Vamm ATTU R N EYS 3,000,266 OMATIC OPERATION OF 5 Sheets-Sheet 2 ABLE BARREL AND SLIDABLE RECEIVER O. B. VARONA SEMI-AUTOMATIC AND FULL-AUT GAS-OPERATED FIREARM WITH SLID Sept. 19, 19

Filed July 29, 1959 MN m SQ Sept. 19, 1961 o. B. VARONA 3,000,266

SEMI-AUTOMATIC AND FULL-AUTOMATIC OPERATION OF GAS-OPERATED FIREARM WITH SLIDABLE BARREL AND SLIDABLE RECEIVER 5 Sheets-Sheet 3 Filed July 29, 1959 K ELL l1 United This invention relates to firearms particularly of the type generally referred to as army rifles, and in particular, a carbine of the gas-actuated type and in which an automatic reloading action is controlled to such an extent that it is possible to hold the firearm exactly on a target so that in both semi-automatic and full-automatic operation of the firearm the parts are stabilized.

The purpose of this invention is to provide a firearm of the gas-operated type in which the receiver and operating elements associated with the bolt remain stationary with the firearm set for semi-automatic operation and in which the complete assembly of the breech is adapted to travel forwardly for firing and rearwardly for reloading upon release of the parts by a button for full-automatic operation of the firearm.

In firearms of the type used for semi-automatic operation and which are adapted to be converted into fullautomatic operating firearms, the reciprocating action resulting from the recoil and return movements makes it difficult to hold the firearms directly upon a target and for this reason semi-automatic firearms that include conversion elements whereby the firearm is adapted to be converted into full-automatic operation are not universally accepted.

With this throught in mind, this invention contemplates a fire arm having a comparatively short bolt action and in which the bolt is actuated by a gas piston which kicks the operating slide rearwardly and in which a springactuated bolt which is released by a trigger-actuated sear picks up and fires a cartridge substantially instantaneously.

The object of this invention is, therefore, to provide means for forming a firearm of the type adapted to be readily converted from semi-automatic to full-automatic operation in which the firearm is adapted to be held on a target in both positions.

Another object of the invention is to provide means for forming a firearm whereby, in firing, the piston of the gas port kicks an operating slide rearwardly and wherein rearward movement of the operating slide ejects the shell.

A further object of the invention is to provide a firearm adapted to be readily converted from semi-automatic to full-automatic operation in which the firearm is of a comparatively simple and economical construction.

With these and other objects and advantages in view, the invention embodies a firearm of conventional carbine design having a barrel mounted in a stock with a bolt slidably mounted in a breech and in which the bolt, hammer, and trigger assembly is retained in operative position with a latch and wherein the latch is adapted to be actuated to release the assembly for full-automatic operation of the firearm.

Other features and advantages of the invention will appear from the following description taken in connection with the drawings, wherein:

FIGURE 1 is a side elevational view of the improved firearm with parts of the barrel and stock broken away.

FIGURE l-A is a side elevational view showing the extended end of the barrel with the muzzle brake on the extended end of the barrel.

FIGURE 2 is a plan view of the firearm also with parts of the barrel and stock broken away.

rates Patent G Patented Sept. 19, 1961 ICE FIGURE 2-A is a plan view of the extended end of the barrel with the muzzle brake thereon and with the parts as shown in FIGURE l-A.

FIGURE 3 is a longitudinal section through the intermediate part of the firearm with the parts shown in automatic firing position and wherein a cartridge is in position to be fired.

FIGURE 4 is a longitudinal section similar to that shown in FIGURE 3, with the firearm in automatic firing position and showing the operating slide driven rearwardly by the gas piston and showing the trigger assembly in a forwardly disposed position.

FIGURE 5 is a longitudinal section through the breech portion of the firearm in semi-automatic firing position and with the parts shown in the cocked position, the parts being shown on an enlarged scale.

FIGURE 6 is a cross section through the breech portionof the firearm taken on line 6-6 of FIGURE 5.

FIGURE 7 is a longitudinal section, similar to that shown in FIGURE 5, but in automatic firing position and also with the parts shown on an enlarged scale and showing the parts with the hammer in the position of firing a cartridge.

FIGURE 8 is a cross section through the interme diate portion of the firearm taken on line 8-8 of FIG- URE 7, illustrating the mounting of the safety button, hammer, and sear.

FIGURE 9 is a cross section through the stock of the firearm with the parts shown on an enlarged scale, illustrating the latch for retaining the parts of the firearm in the semi-automatic operating position and showing the position of the latch or button wherein the rod of the receiver is released.

FIGURE 10 is a section similar to that shown in FIG- URE 9 taken on line 10-10 of FIGURE 1, illustrating the position of the button or latch for retaining the parts of the firearm in the semi-automatic position.

FIGURE 11 is a plan view of the intermediate portion of the stock of the firearm, illustrating the cavity in which the operating elements are positioned.

FIGURE 12 is a longitudinal section through the rear portion of the stock at the end of the cavity, said section being taken on line 1212 of FIGURE 11.

FIGURE 13 is a section taken on line 13-13 of FIG- URE 2 showing a screw for securing an L-shaped mounting bracket in the stock of the firearm.

FIGURE 14 is a side elevational view showing a scar actuator for releasing the trigger in full-automatic operation of the firearm.

FIGURE 15 is a plan view of in FIGURE 14.

FIGURE 16 is a side elevational view of the forward end of the firearm looking toward the side opposite to that shown in FIGURE 1, showing a clamp for retaining the barrel in the end of the stock and with parts of the barrel and stock broken away.

the sear actuator shown FIGURE 17 is an end elevational view of the belt of the firearm with other parts of the firearm omitted.

Referring now to the drawings, wherein like reference characters denote corresponding parts, the improved structure for converting a carbine from semi-automatic to full-automatic position of this invention includes a sear actuator 10 adapted to be pivotally mounted on a pin 11 on which a hammer 12 is pivotally mounted and the sear actuator is provided with an arcuate flange 13 that is positioned to ride against a lower edge 14 of a plate 15 positioned in a cavity 16 extended through a stock 17, and the plate is provided with a flange 18 from which a tube 19 extends, the tube 19 being positioned to receive a stem 20 extended from a receiver 21 and having notches 22 and 23 therein into which a projection 24 0f a button, or latch 25, in a vertically disposed tube 26, extends whereby spouse the receiver is adapted to be locked by the latch or button 25 in the semi-automatic position, and released by pressing the latch inwardly, to the position shown in FIG- URE 9 for full-automatic operation.

In the design shown, the tube 26 and also the latch 25 which is slidably mounted in the tube are square in cross section and, as illustrated in FIGURES 9 and 10, the latch 25 is provided with a stem 27 on which a spring 28 is positioned, the spring being adapted to urge the latch upwardly. The lower end of the tube 26 is provided with a threaded opening 29 and a screw 30' which extends through an opening 31 in the lower part of the Stock 17 retains the tube in an opening 32 with the tube 19 positioned in a recess 33. This unit of the firearm is also retained in position by a screw 34 which extends through an opening 35 in the side of the stock 17, the inner end of the screw being threaded into a lug 36 on the outer surface of the plate 15.

With the firearm horizontally positioned, the gas piston drives the receiver assembly rearwardly until the notch 23 receives the latch 25, however, with the muzzle of the gun extended downwardly, the driving force of the gas piston may only be sufficient to carry the receiver to such a position that the latch 25 snaps into the notch 22. A tooth 37 positioned between the notches 22 and 23 is provided with an arcuate lower surface 38 which makes it possible for the stem to slide over the latch 25 with the firearm in the horizontally disposed position.

The hammer 12, bolt 39 and trigger 40 of the firearm are of conventional design and the parts are mounted and actuated by conventional means.

As illustrated in FIGURES 9 and 10, the latch 25 is provided with an arcuate recess 41 which with the latch pressed inwardly to the position shown in FIGURE 9 receives the stem 20 whereby the stem, receiver, and bolt and trigger assembly are free to slide forwardly and rearwardly for full-automatic operation with the arcuate flange 13 of the sear actuator sliding on the lower edge 14 of the plate as the assembly is moved forwardly by a spring 42 whereby an arm 43 on the clip 10 extends over a side plate 44 of the trigger mounting frame and engages a scar 45 to release the hammer. By this means, the bolt, receiver, and trigger assembly are driven rearwardly by the gas piston with the bolt 39 moving the hammer 12 downwardly until the forward end of the sear 45 snaps into a notch 46 of a segment 47 extended from the lower end of the hammer and with the latch 25 held downwardly the rebound carries the parts forwardly with the arm 43 of the sear actuator 10 again actuating the sear to release the trigger.

With the parts patterned and assembled in this manner, it is only necessary to hold the latch 25 downwardly, as illustrated in FIGURE 9, wherein the recess 41 is positioned to receive the stem to use the firearm for fullautomatic operation. However, it for any reason the latch is released the spring 27 will urge the latch into the notch 23 and the receiver and bolt and trigger assembly will be held stationary, in the position shown in FIG- URE 5, by the latch 25 with the latch released, as illustrated in FIGURE 10, wherein the projection 24 extends into the notch 23 of the stem 20. With the projection 24 extended into the notch 23, the firearm is in position for a semi-automatic rate of fire. In this position, the firearm is cocked as the parts are driven rearwardly by the gas piston and the hammer '12 is-released by the trigger to fire the firearm. V

The bolt 39 is adapted to be driven rearwardly by an operating slide 48 which receives the kick of a gas piston 49, the bolt 39 passing into a cavity 50 in the receiver 21 and a lower surface 51 of the bolt sliding over the upper end of the hammer 12 moving the hammer downwardly, to the position shown in FIGURE 5 wherein the forward tip of the sear snaps into the notch 46. The sear is pivotally mounted on a pin 52 and the rear portion is positioned to rest upon a projection 53 which extends 4 from the trigger 40. The trigger is retained in operative position with a spring 54.

The hammer 12 is forced forwardly by a spring 55 on a pin 56 that is slidably mounted in an opening 57 in the lower portion of the receiver. The forward end of the pin 56 is pivotally connected to the hammer 12 with a p The bolt 39 is conventional having a firing pin 59 with a tip 60 on the forward end and a head 610 that is positioned to be engaged by the hammer 12 and, as illustrated in FIGURE 17, the leading end of the bolt is provided with an extractor 61 and an ejector 62. The bolt is also provided with a key 63 that is retained in a recess 64 in the forward part of the receiver 21, and a lug 65 that is positioned to be engaged by a cam surface 66 on the operating slide to turn the bolt and to release the key 63 from the slot 64. These parts are conventional.

The forward end of the operating slide 48 is provided with a socket 67 that is positioned to receive the gas-port piston 49, as shown in FIGURE 3, and a spring 68, which is secured to the operating slide at a point 69 and which is secured in a tube 70 provides means for returning the operating slide to the position shown in FIGURE 3.

The trigger assembly is provided with a trigger guard 71 and the outer portion of the stock is provided with an arcuate shield 72, the forward end of which is retained in position on a barrel 73 with a screw 74. The barrel is slidably mounted in a tip 75 at the forward end of the stock with a ring clamp 76 which has a ring portion that extends around the barrel and a pair of flanges 7'8 and 79 that extend around the tip and the flanges 78 and 79 are secured to the tip 75 by a screw 77 which extends through the flanges 78 and 79 of the clamp.

The forward end of the barrel 73 is provided with a muzzle brake, as indicated by the numeral 80, and a sight 81 is positioned on the upper surface of the muzzle brake. A conventional adjustable sight 82 is also provided on the upper surface of the receiver.

As illustrated in FIGURES 11 and 12, the stock 17 is provided with a cavity 16 through which the trigger assembly extends and also a recess 83 in which the forward end of the trigger-mounting frame is positioned, as shown in FIGURE 7. The stock is also provided with a semi-circular recess 84 that is positioned to receive the barrel 73 and the recesses 32 and 33 in which the tubes 26 and 19 are positioned are provided at the opposite end. The stock is also provided with a recess 86 that is positioned to receive the lower portion of the plate 15 and a notch 87 in which the lug 36 is positioned. The recess 86 provides clearance for the arcuate flange 13 that slides on the lower edge 14 of the plate 15 whereby the flange is free to move the sear actuator 10 downwardly to actuate the sear to release the hammer in full-automatic operation of the firearm.

With the parts assembled as illustrated and described, a semiand full-automatic gas-operated firearm is provided and the firearm is particularly designed to be used as a shoulder weapon. By this means, a firearm is provided in which the group shots are concentrated on the target in full-automatic operation thereof and in which the shots in full-automatic operation are controlled by the person firing the firearm and wherein the person operating the firearm controls the direction of fire making it possible to use the firearm vertically, diagonally, or horizontally or at any angle Ywithout releasing the trigger while changing the direction of fire.

This firearm provides a weapon in which the recoil of the rifle in full-automatic fire does not aifect the standing position of the person using the firearm. I

This improved structure also provides a firearm of this character in which the firearm is changed to fullautomatic fire with a push button instead of the conventional trigger and in which the whole receiver, bolt, hammer and trigger assembly slides forwardly and rearwardly in full-automatic operation whereby the recoil of the firearm is absorbed in full-automatic operation.

In this firearm, the receiver, bolt, hammer and trigger assembly remains stationary in semi-automatic operation which increases accuracy particularly in shooting to pick up a target. The operating mechanism of the firearm, therefore, remains stationary in semi-automatic operation and is held by a button or latch whereby upon pressing the button inwardly the parts are released and a full-automatic firearm is provided. In full-automatic operation, the complete receiver, bolt, hammer and trigger assembly reciprocate in the stock with the barrel, the parts being driven rearwardly by the gas piston and returned by springs.

It will be understood that modifications, within the scope of the appended claims, may be made in the design and arrangement of the parts, without departing from the spirit of the invention.

What is claimed is:

l. A firearm comprising a stock having a cavity therein, a barrel slidably mounted in the stock, a receiver slidably mounted in the cavity of the stock, a bolt having a firing pin therein slidably mounted in the receiver, a hammer, sear and trigger assembly positioned in the receiver, a plate also positioned in the cavity in the stock, latching means for retaining the receiver in position for semi-automatic operation of the firearm, said plate having an inclined lower edge, and a sear actuator pivotally mounted in the receiver and having a projection positioned to ride on the inclined lower edge of the plate whereby upon forward movement of the receiver, in fullautomatic operation of the firearm, the sear is actuated by the engagement of the projection on the sear actuator with the lower edge of the plate to release the hammer.

2. A firearm comprising a stock having a cavity therein, a barrel slidably mounted in the stock, a receiver slidably mounted in the cavity of the stock, a bolt having a firing pin therein slidably mounted in the receiver, a hammer, sear and trigger assembly positioned in the receiver, a plate also positioned in the cavity in the stock, latching means for retaining the receiver in position for semi-automatic operation of the firearm, said plate having an inclined lower edge, and a sear actuator pivotally mounted in the receiver and having an arcuate flange on one side adapted to slide on the inclined lower edge of the plate and an arm extended from the opposite side, said arm of the sear actuator being positioned to engage the forward end of the sear of the firearm whereby upon forward movement of the receiver the arcuate flange of the sear actuator sliding against the inclined lower edge of the plate moves the sear actuator downwardly whereby the arm thereof actuates the sear to release the hammer.

3. A firearm comprising a stock having a cavity therein, a barrel slidably mounted in the stock, a receiver slidably mounted in the cavity of the stock, a bolt having a firing pin therein slidably mounted in the receiver, a hammer, sear and trigger assembly positioned in the receiver, a plate also positioned in the cavity in the stock, said plate having a tube extended rearwardly from one end, a latch positioned in one side of the tube, a stem having notches in one side extended from the receiver into the tube and positioned whereby the notches coact with the latch for retaining the receiver in position for semi-automatic operation of the firearm, said plate having an inclined lower edge, and a sear actuator pivotally mounted in the receiver and having a projection adapted to ride on the inclined lower edge of the plate whereby upon forward movement of the receiver, in full-automatic operation of the firearm, the sear is actuated to release the hammer.

4. In a firearm, the combination which comprises a stock having a cavity therein, a barrel slidably mounted in the forward end of the stock, a receiver slidably mounted in the cavity of the stock and positioned to slide longitudinally therein, a bolt having a firing pin therein slidably mounted in the receiver, a hammer, sear, and trigger assembly positioned in the receiver, a plate also positioned in the cavity in the stock and having an inclined lower edge positioned at one side of the receiver, said plate having a tube extended rearwardly from one end, a vertically disposed tube extended through one side of the tube extended from the plate, a latch having an upper end in the form of a button slidably mounted in the vertically disposed tube, resilient means in the vertically disposed tube for urging the latch upwardly therein, means for securing the vertically disposed tube in the stock, a stem having notches in one side extended from the receiver into the tube having the vertically disposed tube in one side and positioned whereby the latch forming the button is positioned to coact with the notches for retaining the receiver in position for semi-automatic operation of the firearm, and a sear actuator pivotally mounted in the receiver and having an arcuate flange extended from one side and positioned to ride on the .lower inclined edge of the plate whereby upon forward movement of the receiver in the firing operation the end of the sear actuator on which the arcuate flange is positioned is forced downwardly by the inclined lower edge of the plate, an arm extended from the opposite side of the sear actuator and whereby the arm extended from the opposite side of the sear actuator and which is positioned to engage the upper surface of the forward end of the sear, urges the sear downwardly whereby the hammer is released for firing.

5. In a firearm, the combination which comprises a stock having a cavity therein, a barrel slidably mounted in the forward end of the stock, an arcuate shield positioned over the barrel and means for securing the arcuate shield in position in circumjacent relation to the barrel, 2. receiver slidably mounted in the cavity of the stock and positioned to slide longitudinally therein, a. bolt having a firing pin therein slidably mounted in the receiver, a hammer, sear, and trigger assembly positioned in the receiver, a plate also positioned in the cavity in the stock and having a plate with an inclined lower edge positioned at one side of the receiver, said plate having a tube extended rearwardly from one end, a vertically disposed tube extended through one side of the tube extended from the mounting bracket, a latch having an upper end in the form of a button slidably mounted in the vertically disposed tube, resilient means in the vertically disposed tube for urging the latch upwardly therein, means for securing the vertically disposed tube in the stock, a stem having notches in one side extended from the receiver into the tube having the vertically disposed tube in one side and positioned whereby the latch forming the button is positioned to coact with the notches for retaining the receiver in position for semi-automatic operation of the firearm, and a sear actuator pivotally mounted in the receiver and having an arcuate flange extended from one side and positioned to ride on the lower inclined edge of the plate whereby upon forward movement of the receiver in the firing operation the end of the sear actuator on which the arcuate flange is positioned is forced downwardly by the inclined lower edge of the plate, said sear actuator having an arm extended from the opposite side of the sear actuator which is positioned to engage the upper surface of the forward end of the sear, so that when the arm urges the sear downwardly the hammer is released for firing.

References Cited in the file of this patent UNITED STATES PATENTS Chevallier et al. June 6, 1950' 

